1. Field of the Invention
The invention relates to a recording apparatus, particularly to a recording apparatus for recording according to ink jet printing, and further to an ink jet recording apparatus provided with a data count means for counting drive data.
2. Related Background Art
In the conventional recording apparatus according to ink jet printing, counting the number of drive data on emission of ink from a recording head is a technique required for preventing a nozzle (outlet) of a recording head from being blocked. Determining the time of recovery by absorption performed for removing foams generated in a recording head, controlling a rise of temperature in a recording head and detecting the residual quantity of ink in an ink reservoir for supplying ink to a recording head may also be used. For example, the technique for counting the number of drive data on emission from a recording head, controlling temperature and controlling discharge is disclosed in U.S. Pat. Nos. 4,791,435 and 4,910,528. Japanese Patent Publication No. 5-19467(1993) discloses that residual quantity of ink in an ink reservoir can be detected by counting the number of drive data on emission of ink from a recording head.
Recently, for example, the number of ink nozzles of a recording head is increased from 64 to 128 and the frequency of emission of ink is also increased from 5 kHz to 10 kHz. Further, the recording density of a recording head is also increased from 300 dot per inch (dpi) to high resolution such as 600 dpi.
In the meantime, a technique of so-called multidroplet in which the discharge of ink per recording operation is decreased and a plurality of ink droplets are emitted for one pixel to form an image, is being realized in such a high definition recording head. To realize this technique, a mode for data transfer from a recording apparatus to a recording head is required to be changed from serial transfer to parallel transfer, so as to increase the number of drive data regarding emission of ink from a recording head which must be counted in a fixed time and maintain the speed of recording operation at a high speed is also used. Further, to count the number of drive data on emission of ink from a recording head on such a condition, high-speed counting operation with precision in counting maintained to some extent is required.
A method in which precision in counting the number of drive data on emission of ink from a recording head is disclosed in Japanese Patent Publication No. 3-31352(1991). However, this method cannot be used particularly for controlling or estimating temperature in a recording head.
To change a mode for data transfer to a recording head from serial transfer to parallel transfer and to count entire drive data in data lines for parallel transfer at a high speed a counter must be provided for each of the data lines and data in the counters must be added at a high speed. As a result, a problem that the constitution of the circuits is of large size occurs.
In the present circuitry technology, in case counting speed is not taken into consideration, the number of data can be counted by mounting multiple counters. However, to take the above-described frequency of emission of ink into consideration and add data on emission of ink from a plurality of nozzles of a recording head at a high speed, special circuitry is required. As a result, a problem that it increases the cost of the system occurs.
Further, when a color ink jet recording apparatus developing in the market at present (wherein four recording heads are mounted) is taken into consideration in addition to the conventional monochrome ink jet recording apparatus, the requirement for high speed is more severe and a problem that the constitution of the circuitry is of large size is more serious.